01 -
Preheat oven to 350°F (175°C). Line a 9x13-inch baking dish with parchment paper.
02 -
Mix graham cracker crumbs, melted butter, and sugar until well combined. Press the mixture firmly into the bottom of the prepared pan to form a crust.
03 -
In a large bowl, whisk together sweetened condensed milk, sour cream, lemon juice, and lemon zest until smooth.
04 -
Pour the filling over the crust and spread it evenly.
05 -
Bake for 20–25 minutes, just until set. Avoid browning the top.
06 -
Let the bars cool to room temperature, then refrigerate for at least 2 hours.
07 -
Cut into bars and top with whipped cream or powdered sugar before serving, if desired.